Effect of MnS and Its Size on the Heterogeneous Nucleation and Precipitation of Bismuth in Steel

摘要

The effect of MnS and its size on the heterogeneous nucleation and precipitation of Bismuth was investigated. The results show that bismuth segregates at grain boundaries and suppresses the growth of grains in steel without MnS inclusion. While in steel containing MnS inclusion, bismuth segregates at the MnS/substrate interfaces and MnS can act as an effective nucleus for the heterogeneous nucleation of bismuth. The segregation degree of bismuth is reduced in steel with MnS inclusion, which may be because of the fact that MnS particles provide more interfaces for bismuth to distribute. Moreover, according to the experimental results, the optimum size of MnS for the heterogeneous nucleation of bismuth is 1-2.72 mu m in diameter.